The causes of digestive disorders are multiple. Sometimes a digestive disorder is restricted to the digestive system, and sometimes it is a symptom of a wider systemic problem.
Some digestive disorders could have more than one cause, as well as multiple symptoms, and could affect more than one section of the digestive system.
Many different factors cause digestive diseases. Some common causes are bacterial infection, viral infection, inflammation, lactase deficiency, difficulty digesting certain foods, poor circulation to the intestines or other organs, ruptured or perforated organs, muscle dysfunction, gallstones, stress, and side effects of anti-inflammatory drugs.
Dietary factors include overeating, eating too much fatty food, not consuming enough fiber, and consuming too much alcohol. Smoking can also contribute to some digestive diseases, including ulcers and gastric acid reflux.
While a disorder could have a specific cause, there could be other factors exarcebating the symptoms. The causes of some digestive disorders, such Irritable Bowel Syndrome, are not clear, says the Merck Manuals.
A good example of a cause and a contributory factor to a disorder would be in the case of a stomach ulcer, which is caused by the bacterium helicobacter pylori, but the pain caused by a stomach ulcer could be made worse by the eating of spicy food and the drinking of alcohol.
Some digestive disorders are long-lasting and serious, whereas others resolve themselves in a few days and have no permanent effects.
Food allergies and food intolerance: Read more here about the difference between food allergies and food intolerance. Certain foods can cause allergic reactions, including the swelling of the lips, mouth, the back of the throat. They can also lead to nausea and vomiting, but this will take longer to develop. Abdominal pain can also be caused by food intolerance.
Poor diet: A diet high in fatty, fried and sugary foods and low in fibre can cause stool to pass more slowly through the colon. Inadequate water intake can also lead to constipation, and this can contribute to many other digestive disorders.
Viral or bacterial infection: and parasites. Bacteria, viruses and parasites can get into the digestive system by means of contact with contaminated surfaces, or contact with infected stools and then ingesting the germs or from eating infected food or drinking infected water.
Salmonella, Escherischia coli, cholera and the rotavirus can cause bacterial infections. So-called ‘stomach flu’ is actually gastro-enteritis, which can be caused by bacteria, viruses and parasites. The most common symptom of all of these is acute diarrhoea. Antibiotics can be used to treat bacterial and parasitic infections, but not viral infections. Dehydration is the biggest danger of acute diarrhoea, especially in young children.
Inflammation and auto-immune diseases: These disorders, in which the immune system attacks and harms the body’s own tissues, can involve any part of the digestive system, according to the journal Maedica.
Auto-immune diseases that affect the digestive tract include systemic lupus erymathosus, rheumatoid arthritis, Sjögren’s Syndrome and scleroderma, to name but a few. Systemic autoimmune diseases cause a variety of gastro-intestinal problems.
Structural causes: A structural abnormality in the digestive system (such as the pouches that develop in the intestines of someone with diverticulosis) can hamper the working of the digestive system. An ulcer in the stomach lining or the intestines would be another example, as would be a cancerous tumour.
Genetic causes: Some digestive diseases are thought to be hereditary. These include colon cancer, Crohn’s disease, diabetes type 1, pancreatic cancer, hypothyroidism, cystic fibrosis, coeliac disease and some liver diseases. As the digestive system consists of so many different parts, only the most common ones are listed here. Read more about the organs of the digestive system and what could go wrong with them.
Lifestyle choices: Constant high stress levels, a lack of exercise, smoking, and drinking can all affect the digestive system. While it is difficult to isolate a single cause of something such as GORD, healthy lifestyle and diet choices can relieve the severity and the frequency of episodes of this disorder.
Medication side effects: Many medicines, such as certain antibiotics and non-steroidal anti-inflammatories and certain diabetes medications, to name but a few, can have side effects that involve the digestive system. Nausea, diarrhoea, ulceration and constipation count among these.
Cancer: Gastro-intestinal cancer is term for the group of cancers that affect the digestive system, says the GI Cancer Institute. This includes cancers of the throat, gallbladder, liver, pancreas, stomach, small intestine, large intestine and anus. Cancer is a malignant growth or tumour caused by an uncontrolled division of cells, which can spread into surrounding tissues.
Post-surgical effects: Surgery changes most of the time that anatomy of the digestive tract. Problems include chronic diarrhoea after gall bladder surgery or resection of part of the bowel, pain or even obstruction of the bowel, malabsorption (i.e. vitamin B12 deficiency in surgery for Crohn’s disease, or iron deficiency after stomach resection, etc.), and diabetes after pancreas resection.
Functional problems: Very commonly patients experience symptoms related to the gastro-intestinal system, but all the tests are normal. This can be frustrating to both patient and doctor, because it is difficult to treat. Irritable bowel syndrome is one of these functional disorders. The tests usually exclude other serious diseases such as cancer, but the symptoms often affect the patient’s quality of life.
Ageing: Unfortunately the gastrointestinal system ages with the rest of our bodies. Our saliva decreases, taste is affected, reflux gets worse, motility if affected, diverticular disease develops, etc. We should also be aware that the risk for certain cancers also increases. Recent onset of new symptoms should therefore not be ignored.
Systemic diseases: Many systemic diseases affect our gastrointestinal system, such as autoimmune diseases (i.e. scleroderma that affects the motility of the gut), heart failure (the chronic congestion can cause liver cirrhosis), genetic diseases, HIV and diabetes.
Reviewed by Dr Estelle Wilken (MBChB) (MMed Int) ,Senior Specialist, Internal Medicine and Gastroenterology, University of Stellenbosch and Tygerberg Hospital. February 2016.